This invention relates in general to cable ladders used in telecommunications switching centers. More particularly, the invention relates to an adjustable height cable retaining post for a cable ladder.
Without limiting the scope of the invention, its background is described in connection with cable ladders in a telecommunications switching center, as an example. The backbone of a telecommunications network consists of switching centers and either wireless or wireline communication links coupling the switching centers. A switching center is a place where telephone and electronic communications are routed from one point to another point in the network service area. The switches and equipment in a switching center are customarily mounted in a component cabinet for protection. Typically, component cabinets are installed in rows with cabinets placed side-by-side to form what is known in the industry as a xe2x80x9csuite.xe2x80x9d Suites of component cabinets are also placed back-to-back to create a xe2x80x9cdouble suite.xe2x80x9d
In order to route cables from equipment in one component cabinet to equipment in another component cabinet across an aisle, across the room, or even to another switching center, cable ladders are used to support the cables outside of the component cabinets. Cable ladders, also known as cable raceways, are used to route cables between telecommunications component cabinets. Typically, the cable ladders are installed at an overhead height which allows people to walk beneath the cable ladders to service the component cabinets.
Essentially, a cable ladder comprises an open ladder structure with multiple rungs between two parallel rails that serve to support the cables. The cable ladder has vertical posts attached to the rails to keep cables from falling over the sides of the cable ladder. Each of the vertical posts may be referred to as a xe2x80x9ccable hornxe2x80x9d or a xe2x80x9ccable retaining postxe2x80x9d.
Those skilled in the art will recognize that switching centers are typically xe2x80x9corderedxe2x80x9d environments so everything in a switching center has a proper place similar to a hospital operating room. Thus, neat and orderly cables are an important feature for a cabling system in a switching center. In order to maintain an orderly installation and give the cable ladder a neat appearance, the cables are often sewn onto the cable ladder. An installation technician typically loops a waxed string around a rung of the cable ladder, then the string is tightly sewn around the cables. Waxed string is used so the string will be less likely to slip and loosen with age.
Since the cables must be sewn at many intervals along a cable ladder to properly fasten the cables, it is a very labor intensive, time consuming, and expensive process. When a cable needs to be removed, a considerable amount of work is required to remove the cable, unsew it, replace it and resew the new cable in position. While this process would be easier if the cables were loose on the cable ladder, such an arrangement would be disorderly and unsightly. In addition, even when sewn together the cables are exposed to possible damage from falling objects or other accidental interferences.
Recently, a panel system has been developed to hide the cables routed over a cable ladder between component cabinets. A panel system of this type is disclosed in the Related Application. However, panel systems, such as those in the Related Application are installed on non-adjustable cable retaining posts. Thus, individual panels of the installed panel system may not be entirely level with respect to one another, due to, for example, variances in the installation such as an unlevel floor or other unlevel condition within the telecommunications switching center. In such instances, the panel system will be unlevel, slanted at an angle relative to the floor. As such the ability to adjust the panel system to accommodate an unlevel floor or other variances in the installation is desired.
For stability, ease of installation, and improved appearance, accordingly, a cabling system that eliminates the problems associated with the use of prior art, nonadjustable cable ladder panel systems would provide numerous advantages.
The following invention provides a cabling system and method for leveling a plurality of adjustable cable retaining posts along a cable ladder. An appropriate number of adjustable cable retaining posts are attached to the cable ladder and then adjusted so that the height of each post are at a uniform level and are attached so that the posts are generally level in relationship to either the switching center, the component cabinets, or other cable retaining posts. A leveling device can be used to align the cable retaining posts.
In one embodiment, the height of the cable retaining post is locked relative to the cable ladder. For example, a jam nut may be tightened against the adjustable cable retaining post to lock the post in place. Next, a panel system is placed over the cable ladder and installed on the adjustable cable retaining post. Finally, the level of the panel system is checked and each adjustable cable retaining post is adjusted for final placement of the panel system.
Also disclosed is a cabling system for a telecommunications switching center. The cabling system is capable of adjusting to accommodate disturbances such as uneven floors or cabinet manufacturing variances within the telecommunications switching center. The cabling system comprises two or more component cabinets, cables routed between the component cabinets, one or more cable ladders arranged to support the cables, and a plurality of adjustable cable retaining posts along the cable ladders. The adjustable cable retaining posts are generally level and square in relationship to either the switching center, the component cabinets, or other adjustable cable retaining posts.
In one embodiment, the cable retaining post comprises a rod and a means for adjustably attaching the rod to a cable ladder so that the rod is held in a vertical position along the side of the cable ladder and the rod is adjustable in height with respect to the cable ladder.
In another embodiment, the means for adjustably attaching the rod to the cable ladder is a C-shaped bracket. The C-shaped bracket has a top plate which fits over a side rail of the cable ladder. The top plate also has a hole adapted to receive the rod. The C-shaped bracket has a bottom plate which fits beneath the side rail and a hole which is threaded to engage a threaded portion of the rod. The top plate and the bottom plate are joined by a back plate. The C-shaped bracket is placed around the side rail of a cable ladder and the rod is inserted through the top hole and threaded into the bottom hole to lock the C-shaped bracket in place around the side rail of the cable ladder.
In another embodiment, a jam nut is also threaded onto the rod. The jam nut is tightened against the C-shaped bracket to lock the rod in place in the C-shaped bracket. This keeps the rod from rotating and moving up and down with respect to the cable ladder when a panel system is bolted to the top of the rod. For example, if the rod were not locked with respect to the C-shaped bracket and a panel system retaining bolt was tightened against the top of the rod, the rod could turn and move up or down, thus making the panel system installation unlevel. The top plate also has a left and right notch formed between the left and right edges of the top plate and the back plate. The notches allow the top plate to uniformly flex when the jam nut is tightened down against the top plate. If the notches were not in the top plate, the plate would bend and the rod would deflect out of the desired vertical position.
A technical advantage of the present invention is the ease of installation due to the simplicity of installing the C-shaped bracket and the rod on a cable ladder.
An additional technical advantage of the present invention is that it provides a means to level a panel system installed around the cable ladder as compared to the prior art systems.